U.S. patent application number 10/893241 was filed with the patent office on 2005-02-24 for ketone-aldehyde resins having low water content, high thermal stability and yellowing resistance.
This patent application is currently assigned to DEGUSSA AG. Invention is credited to Andrejewski, Werner, Bergmann, Hans-Peter, Brueckner, Iris, Denkinger, Peter, Ewald, Michael, Gloeckner, Patrick, Weber, Thomas.
Application Number | 20050043499 10/893241 |
Document ID | / |
Family ID | 34042241 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050043499 |
Kind Code |
A1 |
Gloeckner, Patrick ; et
al. |
February 24, 2005 |
Ketone-aldehyde resins having low water content, high thermal
stability and yellowing resistance
Abstract
The invention described herein provides ketone-aldehyde resins,
especially cyclohexanone-formaldehyde resins, with low water
content and high thermal stability and yellowing resistance, and to
a process for preparing them and their use.
Inventors: |
Gloeckner, Patrick;
(Ratingen, DE) ; Andrejewski, Werner; (Dorsten,
DE) ; Bergmann, Hans-Peter; (Marl, DE) ;
Brueckner, Iris; (Dorsten, DE) ; Denkinger,
Peter; (Nottuln, DE) ; Ewald, Michael; (Marl,
DE) ; Weber, Thomas; (Dortmund, DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
DEGUSSA AG
Duesseldorf
DE
|
Family ID: |
34042241 |
Appl. No.: |
10/893241 |
Filed: |
July 19, 2004 |
Current U.S.
Class: |
528/129 |
Current CPC
Class: |
C08G 6/02 20130101 |
Class at
Publication: |
528/129 |
International
Class: |
C08G 008/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 2003 |
DE |
103 35 561.4 |
Claims
1. A ketone-aldehyde resin having a water content of less than 0.4%
by weight, obtained by condensing at least one ketone with at least
one aldehyde in the presence of at least one alkali metal compound
and at least one phase transfer catalyst in the absence of solvent
or in a water-miscible organic solvent, wherein the aldehyde is
added (1) in an initial charge at the beginning of the condensation
and (2) in at least one further substep following initiation of
condensation in (1).
2. A ketone-aldehyde resin as claimed in claim 1, wherein (2) is
performed in two substeps.
3. A ketone-formaldehyde resin as claimed in claim 1, prepared in
the presence of from 0.05 to 10 mol %, based on the ketone, of at
least one alkali metal compound and from 0.01 to 15% by weight,
based on the ketone, of at least one phase transfer catalyst,
wherein from 2 to 40 mol % of the aldehyde are introduced at the
beginning of the reaction, from 20 to 98 mol % of the aldehyde are
supplied in a second step, and from 0 to 40 mol % of the aldehyde
are added in a third step.
4. A ketone-formaldehyde resin as claimed in claim 3, wherein from
2 to 40 mol % of the aldehyde are added in the third step.
5. A ketone-aldehyde resin as claimed in claim 1, wherein the
ketone is selected from the group consisting of acetone,
acetophenone, methyl ethyl ketone, 2-heptanone, 3-pentanone, methyl
isobutyl ketone, cyclohexanone, cyclopentanone, cyclododecanone,
mixtures of 2,2,4- and 2,4,4-trimethylcyclopentanone,
cycloheptanone, and cyclooctanone, cyclohexanone, alkyl-substituted
cyclohexanones having one or more alkyl radicals containing in
total from 1 to 8 carbon atoms, and mixtures thereof.
6. A ketone-aldehyde resin as claimed in claim 4, wherein the
ketone is selected from the group consisting of
4-tert-amylcyclohexanone, 2-sec-butylcyclohexanone,
2-tert-butylcyclohexanone, 4-tert-butylcyclohexanone,
2-methylcyclohexanone, 3,3,5-trimethylcyclohex- anone, and mixtures
thereof.
7. A ketone-aldehyde resin as claimed in claim 1, wherein the
ketone is cyclohexanone or a mixture of cyclohexanone and at least
one other ketone.
8. A ketone-aldehyde resin as claimed in claim 1, wherein the
aldehyde is selected from the group consisting of formaldehyde,
acetaldehyde, n-butyraldehyde, isobutyraldehyde, valeraldehyde,
dodecanal, and mixtures thereof.
9. A ketone-aldehyde resin as claimed in claim 1, wherein the
condensing is conducted in the water-miscible solvent, which is an
aqueous or alcoholic formaldehyde solution, trioxane and/or
paraformaldehyde.
10. A ketone-aldehyde resin as claimed in claim 1, wherein the
alkali metal compound comprises a hydroxide of the cations
NH.sub.4, NR.sub.4, Li, Na, or K.
11. A ketone-aldehyde resin as claimed in claim 1, wherein the
alkali metal compound is potassium hydroxide and/or sodium
hydroxide.
12. A ketone-aldehyde resin as claimed in claim 1, wherein the
phase transfer catalyst is an ammonium compound and/or a
phosphonium compound.
13. A ketone-aldehyde resin as claimed in claim 12, wherein the
phase transfer compound is represented by formula (A) 2wherein X is
a nitrogen or phosphorus atom, R.sub.1, R.sub.2, R.sub.3, and
R.sub.4, are identical or different and are an alkyl radical having
1 to 22 carbon atoms in the carbon chain and/or a phenyl radical
and/or a benzyl radical, and Y is the anion of an (in)organic acid
or a hydroxide ion.
14. A ketone-aldehyde resin as claimed in claim 13, wherein
R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are an alkyl radical having
1 to 12 carbon atoms in the carbon chain and/or phenyl radicals
and/or benzyl radicals.
15. A ketone-aldehyde resin as claimed in claim 13, wherein
R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are an alkyl radical having
1 to 12 carbon atoms.
16. A ketone-aldehyde resin as claimed in claim 1, wherein the
anion of the alkali metal compound comprises Cl.sup.-, Br.sup.-,
I.sup.-, hydroxide, methoxide, or acetate.
17. A ketone-aldehyde resin as claimed in claim 1, wherein the
phase transfer catalyst is selected from the group consisting of
cetyldimethylbenzylammonium chloride, tributylbenzylammonium
chloride, trimethylbenzylammonium chloride, trimethylbenzylammonium
iodide, triethylbenzylammonium chloride, triethyl-benzylammonium
iodide, tetramethylammonium chloride, tetraethylammonium chloride,
tetrabutylammonium chloride and mixtures thereof.
18. A ketone-aldehyde resin as claimed in claim 1, wherein the
condensing is conducted in a water-miscible alcohol and/or
ketone.
19. A ketone-aldehyde resin as claimed in claim 18, wherein the
condensing is conducted in methanol, ethanol, ethyl methyl ketone
and/or acetone.
20. A ketone-aldehyde resin as claimed in claim 1, wherein the
ketone comprises cyclohexanone and the aldehyde comprises
formaldehyde.
21. A ketone-aldehyde resin as claimed in claim 1, which has the
following properties: solubility in alcohols and/or aromatics; a
water content below 0.4% by weight; a high temperature stability; a
nonvolatiles fraction of more than 99% by weight (1 h, 160.degree.
C.); a glass transition temperature of between 10 and 110.degree.
C.; and a hydroxyl number of between 0 and 300 mg KOH/g.
22. A process for preparing a ketone-aldehyde resin having a water
content of less than 0.4% by weight, comprising condensing at least
one ketone with at least one aldehyde in the presence of at least
one alkali metal compound and at least one phase transfer catalyst
in the absence of solvent or in a water-miscible organic solvent,
wherein the aldehyde is added (1) by means of an initial charge at
the beginning of the condensation and (2) in at least one further
substep following initiation of condensation in (1).
23. A process as claimed in claim 22, wherein the phase transfer
catalyst is represented by formula (A) 3wherein X is a nitrogen or
phosphorus atom, R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are
identical or different and are an alkyl radical having 1 to 22
carbon atoms in the carbon chain and/or a phenyl radical and/or a
benzyl radical, and Y is the anion of an (in)organic acid or a
hydroxide ion.
24. A process as claimed in claim 21, wherein said resin is
prepared in the presence of from 0.05 to 10 mol %, based on the
ketone employed, of at least one alkali metal compound and from
0.01 to 15% by weight, based on the ketone employed, of at least
one phase transfer catalyst, wherein from 2 to 40 mol % of the
aldehyde are introduced at the beginning of the reaction, from 20
to 98 mol % of the aldehyde are supplied in a second step, and from
0 to 40 mol %, of the aldehyde are added in a third step.
25. A process as claimed in claim 22, wherein the ketone is
selected from the group consisting of acetone, acetophenone, methyl
ethyl ketone, 2-heptanone, 3-pentanone, methyl isobutyl ketone,
cyclohexanone, cyclopentanone, cyclododecanone, mixtures of 2,2,4-
and 2,4,4-trimethylcyclopentanone, cycloheptanone, and
cyclooctanone, cyclohexanone, alkyl-substituted cyclohexanones
having one or more alkyl radicals containing in total from 1 to 8
carbon atoms, and mixtures thereof.
26. A process as claimed in claim 25, wherein the ketone is
selected from the group consisting of 4-tert-amylcyclohexanone,
2-sec-butylcyclohexanon- e, 2-tert-butylcyclohexanone,
4-tert-butylcyclohexanone, 2-methylcyclohexanone,
3,3,5-trimethylcyclohexanone, and mixtures thereof.
27. A process as claimed in claim 22, wherein the ketone is
cyclohexanone or a mixture of cyclohexanone and at least one other
ketone.
28. A process as claimed in claim 22, wherein the aldehyde is
selected from the group consisting of formaldehyde, acetaldehyde,
n-butyraldehyde, isobutyraldehyde, valeraldehyde, dodecanal, and
mixtures thereof.
29. A process as claimed in claim 22, wherein the condensing is
conducted in the water-miscible solvent, which is an aqueous or
alcoholic formaldehyde solution, trioxane and/or
paraformaldehyde.
30. A process as claimed in claim 22, wherein the basic compound
comprises a hydroxide of the cations NH.sub.4, NR.sub.4, Li, Na, or
K.
31. A process as claimed in claim 22, wherein the basic compound is
potassium hydroxide and/or sodium hydroxide.
32. A process as claimed in claim 22, wherein the phase transfer
catalyst is an ammonium compound and/or a phosphonium compound.
33. A ketone-aldehyde resin as claimed in claim 23, wherein
R.sub.1, R.sub.2, R.sub.3, and R4 are an alkyl radical having 1 to
12 carbon atoms in the carbon chain and/or phenyl radicals and/or
benzyl radicals.
34. A process as claimed in claim 23, wherein R.sub.1, R.sub.2,
R.sub.3, and R.sub.4 are an alkyl radical having 1 to 12 carbon
atoms.
35. A process as claimed in claim 22, wherein the anion of the
basic compound comprises Cl.sup.-, Br.sup.-, I.sup.-, hydroxide,
methoxide, or acetate.
36. A process as claimed in claim 22, wherein the phase transfer
catalyst is selected from the group consisting of
cetyldimethylbenzylammonium chloride, tributylbenzylammonium
chloride, trimethylbenzylammonium chloride, trimethylbenzylammonium
iodide, triethylbenzylammonium chloride, triethyl-benzylammonium
iodide, tetramethylammonium chloride, tetraethylammonium chloride,
tetrabutylammonium chloride and mixtures thereof.
37. A process as claimed in claim 22, wherein the condensing is
conducted in a water-miscible alcohol and/or ketone.
38. A process as claimed in claim 37, wherein the condensing is
conducted in methanol, ethanol, ethyl methyl ketone and/or
acetone.
39. A process as claimed in claim 22, wherein the ketone comprises
cyclohexanone and the aldehyde comprises formaldehyde.
40. A process as claimed in claim 22, wherein the resin has the
following properties: solubility in alcohols and/or aromatics; a
water content below 0.4% by weight; a high temperature stability; a
nonvolatiles fraction of more than 99% by weight (1 h, 160.degree.
C.); a glass transition temperature of between 10 and 110.degree.
C.; and a hydroxyl number of between 0 and 300 mg KOH/g.
41. A composition selected from the group consisting of coating
compositions, printing inks, pigment pastes, tinting pastes,
masterbatches, ballpoint pastes, inks, polishes, adhesives,
sealants, and insulants which comprises the ketone-aldehyde resin
of claim 1.
42. The composition as claimed in claim 41, which dries physically
or oxidatively.
43. The composition as claimed in claim 41, which further comprises
isocyanates and isocyanate derivatives as crosslinkers.
44. The use as claimed in claim 41, which further comprises amine
resins as crosslinkers.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to ketone-aldehyde resins, especially
cyclohexanone-formaldehyde resins, with low water content and high
thermal stability and yellowing resistance, and to a process for
preparing them and their use.
[0003] 2. Description of the Background
[0004] It is known that ketones or mixtures of ketones and
aldehydes can be reacted in the presence of basic catalysts or
acids to form resinous products. Thus mixtures of cyclohexanone and
methylcyclohexanone can be used to prepare resins (Ullmann Vol. 12,
p. 551). Cyclohexanone and formaldehyde react to form hard resins
which are used in the coatings industry.
[0005] Processes for preparing products of this kind are described
in, for example, U.S. Pat. No. 2,540,885, U.S. Pat. No. 2,540,886,
DD 12433, DE 13 00 256, DE 28 31 613, DD 123481 and DE 12 56
898.
[0006] The resins obtained in accordance with the various processes
possess softening points, as apparent from an overview given in DD
123481, of up to 120.degree. C.
[0007] DD 12433 describes a process for preparing gritlike products
by addition of small amounts of swelling agents and thickeners or
surface-active substances as dispersing assistants. Some or all of
these additives may remain in the products, and consequently may
have adverse effects on properties such as the water resistance of
coatings from coating materials manufactured with the products. The
skilled worker is also aware that the proportion of water in
gritlike products is relatively high, since there may be water
inclusions in the grit particles.
[0008] According to DD 123481 and DE 12 56 898 it is possible to
obtain resins having softening points of up to 160.degree. C. The
processes described, however, are costly and inconvenient.
[0009] According to DE 28 31 613 polycondensation products are
obtained from aliphatic or cyclic ketones or mixtures of these
ketones with aliphatic aldehydes in the presence of basic
catalysts, using from 0.005 to 10 mol %, based on the total amount
of ketone and aldehyde, of a phase transfer catalyst. If the
process disclosed therein is used to prepare a resin having a
composition which corresponds to the present invention, high
softening points and hence high molecular weights are obtained.
Since the resins to which the invention relates are used, inter
alia, in the coatings industry in order to reduce the solvent
fraction, such high molecular weights are especially
disadvantageous. The skilled worker is also aware that too high a
molecular weight is detrimental to the broad solubility properties
of cyclohexanone-formaldehyde resins. The skilled worker is further
aware that resins, in accordance with the process disclosed
therein, possess low nonvolatile fractions, as a result of which
the thermal stability may be adversely affected and the yields of
the process described are low.
[0010] DE 12 56 898 and U.S. Pat. No. 2,540,885 describe processes
for preparing condensation products in the presence of inert
solvents. The process on which the present invention is based
succeeds without such additions, thereby obviating expensive
reprocessing of said solvent and, for a given reactor size,
allowing the use of greater quantities of reactants, so that higher
conversions are achieved. The skilled worker is aware that resins,
in accordance with the process described in U.S. Pat. No.
2,540,886, are obtained in low yields.
[0011] DE 13 00 256 describes a process for purifying
ketone-formaldehyde resins. If the conditions there are applied to
the cyclohexanone and formaldehyde condensation products of the
invention the resultant resins, particularly as a 10% strength
solution in xylene, contain an insoluble precipitate.
[0012] JP 47018866 adds an anhydride to a resin to obtain a
low-water-content resin which can find use in polyurethane
applications. The products of the invention have a low water
content, suitable for polyurethane applications, without the
addition of further substances.
[0013] JP 46004998 uses phenols in order to enhance the light
stability and heat resistance of cyclohexanone-formaldehyde resins.
The resins prepared by the process of the invention are stable
without such additives.
[0014] At the present time a variety of cyclohexanone-formaldehyde
resins are available on the market. The products differ primarily
in their softening point (from 75-120.degree. C.) and in their OH
number (from 80-260 mg KOH/g).
[0015] Common to all these products is a fairly high water content
of between 0.4% and 2.5% by weight. The high water content of the
standard commercial products prevents their use in high-grade
coating materials such as 2-component polyurethane varnishes, for
example.
[0016] A further disadvantage of the standard commercial products
is that solutions of these resins in aromatic solvents such as,
say, xylene tend toward clouding owing to the high water content.
These products are unsuitable for applications which use, for
example, long-oil alkyd resins.
[0017] Furthermore, the resins presently available on the market
possess a relatively low temperature stability, and so can be used
only to a limited extent, if at all, in baking systems.
SUMMARY OF THE INVENTION
[0018] The object on which the present invention was based was to
eliminate the aforementioned disadvantages of the commercial
products and to find resins which possess a low water content, high
thermal stability and yellowing resistance and which are soluble in
alcoholic and aromatic solvents. Additionally the nonvolatiles
content ought to be high.
[0019] The intention was further to find a process for preparing
ketone-aldehyde resins, especially cyclohexanone-formaldehyde
resins, with which, on economic grounds, it would be possible to
obtain yields above 92%.
[0020] Surprisingly, it has proved possible to achieve this object
by using a phase transfer catalyst for the resin synthesis and by
adding the required amount of aldehyde in portions.
[0021] Thus, the present invention provides ketone-aldehyde resins
having a water content of less than 0.4% by weight, where the resin
is obtained by condensing at least one ketone with at least one
aldehyde in the presence of
[0022] I. at least one alkali metal compound and
[0023] II. at least one phase transfer catalyst
[0024] in the absence of solvent or using a water-miscible organic
solvent, such as methanol or ethanol, the addition of the aldehyde
being made
[0025] 1. by means of an initial charge at the beginning of the
condensation and
[0026] 2. in at least one further substep following initiation of
condensation in stage 1.
[0027] Accordingly, the present invention relates to a
ketone-aldehyde resin having a water content of less than 0.4% by
weight, obtained by condensing at least one ketone with at least
one aldehyde in the presence of at least one alkali metal compound
and at least one phase transfer catalyst in the absence of solvent
or in a water-miscible organic solvent, wherein the aldehyde is
added
[0028] (1) in an initial charge at the beginning of the
condensation and
[0029] (2) in at least one further substep following initiation of
condensation in (1).
[0030] The present invention also provides a process for making the
ketone-aldehyde resin as described above.
[0031] The present invention also provides compositions which
contain the ketone-aldehyde resin described herein.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The invention provides with preference ketone-aldehyde
resins where stage 2 is performed in two further substeps.
[0033] Great preference is given to ketone-formaldehyde resins
obtained by condensing at least one ketone with at least one
aldehyde prepared in the presence of
[0034] I. from 0.05 to 10 mol % (based on the ketone employed) of
at least one alkali metal compound and
[0035] II. from 0.01 to 15% by weight (based on the ketone
employed) of at least one phase transfer catalyst,
[0036] where
[0037] 1. from 2 to 40 mol % of the aldehyde are introduced at the
beginning of the reaction, and
[0038] 2. from 20 to 98 mol % of the aldehyde are supplied in a
second step, and
[0039] 3. from 0 to 40 mol %, preferably from 2 to 40 mol % of the
aldehyde are added in a third step.
[0040] A further preferred subject of the invention are such
cyclohexanone-formaldehyde resins.
[0041] The ketone-aldehyde resins on which the invention is based
possess a low water content and are therefore suitable for use in
high-grade coating materials such as 2-component polyurethane
varnishes, for example. Furthermore, as a result of the process,
the resins are soluble in alcoholic and aromatic solvents, and so
are suitable for applications in which, for example, long-oil alkyd
resins are used.
[0042] As noted above, the water content of the resin is less than
0.4% by weight. In preferred embodiments, the water content may be
less than 0.3, 0.2 or 0.1% by weight.
[0043] The resins of the invention have only a slight tendency
toward yellowing during thermal exposure. Moreover, the products of
the invention possess a high nonvolatiles content and are therefore
suitable for low-VOC applications.
[0044] It has also been found, surprisingly, that it is possible to
vary the hydroxyl numbers of the resins within wide ranges.
[0045] The yields of the process on which the invention is based
are more than 92%, preferably more than 94%, and, with particular
preference, more than 96% of the theoretical yield.
[0046] The resins of the invention have the following
properties:
[0047] solubility in alcohols, especially ethanol, and/or
aromatics, especially xylene;
[0048] a water content below 0.4% by weight, in particular 0.3% by
weight;
[0049] a high temperature stability, i.e., low yellowing tendency
during thermal exposure;
[0050] a nonvolatiles fraction of more than 99% by weight (1 h,
160.degree. C.);
[0051] a glass transition temperature of between 10 and 110.degree.
C., preferably between 50 and 90.degree. C., more preferably
between 60 and 85.degree. C.;
[0052] a hydroxyl number of between 0 and 300 mg KOH/g.
[0053] Ketones
[0054] Ketones suitable for the ketone-aldehyde resins of the
invention include all ketones, particularly acetone, acetophenone,
methyl ethyl ketone, 2-heptanone, 3-pentanone, methyl isobutyl
ketone, cyclopentanone, cyclododecanone, mixtures of 2,2,4- and
2,4,4-tri-methylcyclopentanone, cycloheptanone, and cyclooctanone,
cyclohexanone and all alkyl-substituted cyclohexanones having one
or more alkyl radicals containing in total from 1 to 8 carbon
atoms, individually or in a mixture. Examples of alkyl-substituted
cyclohexanones include 4-tert-amylcyclohexanone,
2-sec-butylcyclohexanone, 2-tert-butylcyclohexanone,
4-tert-butylcyclohexanone, 2-methylcyclohexanone, and
3,3,5-trimethylcyclohexanone.
[0055] In general, however, it is possible to use any ketones said
in the literature to be suitable for ketone resin syntheses.
Preferred ketone-formaldehyde resins are those based on
cyclohexanone alone or together with acetophenone,
4-tert-butylcyclohexanone and 3,3,5-tri-methylcyclohexanone, methyl
ethyl ketone, and heptanone.
[0056] Aldehydes
[0057] Suitable aldehyde components include in principle branched
or nonbranched aldehydes, such as formaldehyde, acetaldehyde,
n-butyraldehyde and/or isobutyraldehyde, valeraldehyde, and
dodecanal, etc., though preference is given to formaldehyde alone
or in mixtures. In general, however, it is possible to use any
aldehydes said in the literature to be suitable for ketone resin
syntheses. Formaldehyde, which is preferred, is normally employed
in the form of an aqueous or alcoholic solution (e.g., in methanol
or butanol) with a concentration of from about 20 to 40% by weight.
Other forms of formaldehyde, such as para-formaldehyde or trioxane,
for example, are likewise possible. Aromatic aldehydes, such as
benzaldehyde, may likewise be present in a mixture with
formaldehyde.
[0058] Alkali Metal Compound
[0059] The reaction is conducted in a basic medium. In general it
is possible to use any basic compound said in the literature to be
suitable for ketone resin syntheses. Preference is given to
hydroxides, for example, of the cations NH.sub.4, NR.sub.4, Li, Na,
and K.
[0060] Phase Transfer Catalyst
[0061] In the polycondensation mixture, from 0.01 to 15% by
weight--based on the ketone of a phase transfer catalyst of the
general formula (A) 1
[0062] are used, where
[0063] X is a nitrogen or phosphorus atom,
[0064] R.sub.1, R.sub.2, R.sub.3, and R.sub.4 can be identical or
different and are an alkyl radical having 1 to 22 carbon atoms in
the carbon chain and/or a phenyl radical and/or a benzyl radical,
and
[0065] Y is the anion of an (in)organic acid or a hydroxide
ion.
[0066] Preferred alkyl radicals (R.sub.1-4) for quaternary ammonium
salts are those having 1 to 22 carbon atoms, especially those
having 1 to 12 carbon atoms, in the carbon chain and/or phenyl
radicals and/or benzyl radicals and/or mixtures of both. Preference
is given to using benzyltributylammonium chloride,
cetyldimethylbenzylammonium chloride and/or triethylbenzylammonium
chloride. For quaternary phosphonium salts, alkyl radicals having 1
to 22 carbon atoms and/or phenyl radicals and/or benzyl radicals
are preferred for R.sub.1-4. Suitable anions are those of strong
(in)organic acids, such as Cl.sup.-, Br.sup.-, and I.sup.-, for
example, and also hydroxides, methoxides or acetates.
[0067] Examples of quaternary ammonium salts are
cetyldimethylbenzylammoni- um chloride, tributylbenzyl-ammonium
chloride, trimethylbenzylammonium chloride, trimethylbenzylammonium
iodide, triethylbenzylammonium chloride or triethylbenzylammonium
iodide, tetramethyl-ammonium chloride, tetraethylammonium chloride,
and tetrabutylammonium chloride. Examples of suitable quaternary
phosphonium salts include triphenylbenzylphosphonium chloride and
triphenylbenzylphosphonium iodide. Mixtures, however, can also be
used.
[0068] The phase transfer catalyst is used in amounts of from 0.01
to 15%, preferably from 0.1 to 10.0%, and in particular in amounts
of from 0.1 to 5.0% by weight--based on the ketone employed--in the
polycondensation mixture.
[0069] Solvent
[0070] The reaction can be conducted using an auxiliary solvent.
Those which have proven suitable include alcohols such as methanol
and ethanol, for example. It is also possible to use water-soluble
ketones as auxiliary solvents, which then are also incorporated
into the resin by reaction.
[0071] The invention also provides a process for preparing
ketone-aldehyde resins having a water content of less than 0.4% by
weight, obtained by condensing at least one ketone with at least
one aldehyde in the presence of
[0072] I. at least one alkali metal compound and
[0073] II. at least one phase transfer catalyst
[0074] in the absence of solvent or using a water-miscible organic
solvent such as methanol or ethanol, for example, the addition of
the aldehyde being made
[0075] 1. by means of an initial charge at the beginning of the
condensation and
[0076] 2. in at least one further substep following initiation of
condensation in stage 1.
[0077] The invention is a process for which stage 2 is performed
two further substeps.
[0078] A process for preparing ketone-formaldehyde resins obtained
by condensing at least one ketone with at least one aldehyde
prepared in the presence of
[0079] I. from 0.05 to 10 mol % (based on the ketone employed) of
at least one alkali metal compound and
[0080] II. from 0.01 to 15% by weight (based on the ketone
employed) of at least one phase transfer catalyst,
[0081] where
[0082] 1. from 2 to 40 mol % of the aldehyde are introduced at the
beginning of the reaction, and
[0083] 2. from 20 to 98 mol % of the aldehyde are supplied in a
second step, and
[0084] 3. from 0 to 40 mol %, preferably from 2 to 40 mol % of the
aldehyde are added in a third step.
[0085] A further preferred subject of the invention is a process
for preparing cyclohexanone-formaldehyde resins.
[0086] The ratio between the ketone component and the aldehyde
component can vary from 1:0.9 to 1:4. A preferred ketone/aldehyde
ratio, however, is from 1:1 to 1:2.5. The ketone component and the
aldehyde component can be added as they are or in solvents, as
mentioned above, or in aqueous form. Particular preference is given
to using an aqueous or alcoholic formaldehyde solution, trioxane
and/or paraformaldehyde.
[0087] The invention likewise provides for the use of
ketone-aldehyde resins having a water content of less than 0.4% by
weight, obtained by condensation in the presence of
[0088] I. at least one alkali metal compound and
[0089] II. at least one phase transfer catalyst
[0090] in the absence of solvent or using a water-miscible organic
solvent such as methanol or ethanol, for example, the addition of
the aldehyde being made
[0091] 1. by means of an initial charge at the beginning of the
condensation and
[0092] 2. in at least one further substep following initiation of
condensation in stage 1,
[0093] as a main component, base component or additional component
in coating compositions, printing inks, pigment pastes, tinting
pastes, masterbatches, ballpoint pastes, inks, polishes, adhesives,
sealants, and insulants, which dry physically or oxidatively, but
especially with isocyanates and isocyanate derivatives and/or with
amine resins as crosslinkers.
EXAMPLES
[0094] Having generally described this invention, a further
understanding can be obtained by reference to certain specific
examples which are provided herein for purposes of illustration
only and are not intended to be limiting unless otherwise
specified.
[0095] Preparation of a Resin
[0096] The resins are synthesized by charging 1 030 g of
cyclohexanone, 210 g of an approximately 30% strength formaldehyde
solution, 280 ml of methanol, and 3.8 g of benzyltributylammonium
chloride to a three-necked flask with stirrer, reflux condenser,
and temperature sensor under nitrogen. The reaction is initiated by
adding 8.7 g of a 25% strength sodium hydroxide solution. The
temperature of the batch is held below 60.degree. C. by cooling.
Then 1 350 g of an approximately 30% strength formaldehyde solution
are added over the course of 100 minutes, followed by 25.2 g of a
25% strength sodium hydroxide solution. After stirring at reflux,
100 g of an approximately 30% strength formaldehyde solution are
added and stirring at reflux is continued for 4 hours more. The
stirrer is then switched off. Following phase separation, the
supernatant aqueous methanol phase is separated off and the
water/methanol mixture which remains is removed by distillation.
The crude product is washed five times with water, 12 ml of acetic
acid being added to the first wash water. Finally the product is
distilled at up to 165.degree. C. under a water jet vacuum.
[0097] Properties of the Resin
[0098] The resin obtained is colorless, clear, and brittle, soluble
at 10% in ethanol, methyl ethyl ketone, acetone, ethyl acetate and
xylene, and possesses a softening point of 106.degree. C.
[0099] Gardner color number, 50% strength in ethyl acetate: 0.5
[0100] Hazen color number, 50% strength in ethyl acetate: 110
[0101] Karl-Fischer water content: 0.14% by weight
[0102] OHN=96 mg KOH/g, Tg=71.degree. C.
[0103] M.sub.n=650 g/mol, M.sub.w=1 200 g/mol (polystyrene
standard)
1 1 h at 120.degree. C. 1 h at 140.degree. C. 1 h at 160.degree. C.
Color numbers.sup.1) 0.6 0.8 1.6 Nonvolatiles content 99.8 99.6
99.5 [% by wt.] .sup.1)Gardner color numbers, 50% strength in ethyl
acetate, of the resins in 100% form subjected to thermal
exposure
[0104] This application is based on German patent application No.
103 38 561.4, filed on Aug. 22, 2003, and incorporated herein by
reference.
* * * * *